Viral story board Flashcards
Process of fighting a viral infection
1) Virus enters host cells and replicates
2) Host cells begin to release IFN-alpha which causes the host cells to display parts of viral peptide on their surface MHC I molecule. It also prevents neighboring cell from getting infected
3) The virus kills infected cells. Released viral particles activate dendritic cells which engulf the particles. These then transport the particles to the lymph node via the lymphatic system
4) Dendritic cells enter the lymph nodes and cause T cells to enter. Dendritic cells present the viral peptide to naïve T-helper cells on their MHC II molecules which activates the T-cells. The dendritic cells can activate T-helper 1 and T-helper 2 cells
5) Activated T-helper 2 cells cause B cells to become plasma cells and produce antibodies. B cells are activated by T-cells via co-stimulatory molecules and the release of cytokines
6) Activated T-helper 1 cells cause cytotoxic T cells to become activated by releasing cytokines. The activated T-helper cells and cytotoxic T cells leave the lymph node and go to the site of infection
7) At the site of infection, activated cytotoxic T cells kill virally infected cells. They recognize the virally infected cells using the MHC I molecules which present the viral peptide on the infected cell’s surface
8) Natural killer cells get activated by the IFN-alpha released by the infected cells and Il-2 and IFN-gamma released by T-helper 1 cells. The activated natural killer cells then kill virally infected cells
9) Virally infected cells secrete and express viral proteins. These viral proteins can be neutralized or removed by antibodies binding to them. Or, bound antibodies may guide natural killer cells to recognize the infected cells and kill them
What does IFN-alpha do?
Stimulates host cells to display parts of viral peptide on MHC I
What do host cells do when infected with a virus?
Release IFN-alpha
What do dendritic cells do to viral particles?
Engulf them and transport to lymph node via lymphatic system
What happens when dendritic cells enter lymph nodes?
Cause T-cells to enter
How do dendritic cells activate T-cells?
Present viral peptide on MHC II molecules
What do activated T-helper 2 cells do?
Cause B cells to become plasma cells and produce antibodies
How do T-cells stimulate B cells?
Cytokines
How do cytotoxic cells recognise infected cells?
MHC I molecules presenting viral peptide
How are natural killer cells activated?
IFN-alpha released by infected cells
IL-2 and IFN-gamma released by TH1 cells
